3 men stopped at motel to get a room for the night.  The manager
charged $30 for the room and each man paid $10.  After they left, the
manager realized that he charged them $5 too much and asked the bell
boy to take the $5 to the men.  The bell boy realized before he got to
the men's room that he could not divide the $5 equally and decided to
give them each a dollar and keep the other $2 for himself.  After the
men each received their dollar, they would now have paid $9 each
(which equals $27) and $2 to the bell boy for a total of $29 for the
room.  Where's the other dollar?

The other dollar has gone nowhere...
   

"This brainteaser is an example of a false problem. You cannot add the
27$ to the 2$ as the 2$ that is now with the bellboy is actually part
of the 27$ they finally paid for the room!
So there is no question of 1$ being "missing"!
In fact you have to add the 27$ to the 3$ that the men got back.
Although the 3 men paid 27$ they didn't give that money to the
hotelkeeper. The fact is that the 2$ extra that they paid is with the
bellboy.
So the original 30$ is distributed as follows:
hotelkeeper 25$, bellboy 2$, 3 men 3$.
Beware of ostensible reasoning!"
   
http://pgoh.free.fr/answers.html 
  
  
"The calculation of $27 + $2 contains two errors: the manager's $5 is
ignored and the bellboy's $2 is counted in the wrong direction.
The original payment of $30 is correctly accounted for as $27 finally
paid by the three guests, plus $5 refunded by the manager, MINUS $2 kept
by the bellboy (so that only $3 of refund was received)."
  
http://rec-puzzles.org/new/sol.pl/logic/29